Introduction of loop operating system to improve the stability of continuous hydrogen production for the thermochemical water-splitting iodine–sulfur process

The thermochemical water-splitting iodine–sulfur process facilitates hydrogen production. This study proposes a new loop operation by subdividing the process configuration into four sections before transferring the continuous operation. The loop operation should define the section affecting the fluctuations to easily stabilize the system. The proposed loop operation was validated by analyzing the material and heat balances using a process simulator. The calculated results showed that the material balances of the respective loop sections were closed without component discharge to outside sections. The loop operation would transfer to the continuous operation by connecting all sections. Considering the switching of operation modes, the material and heat balance showed no or little difference, indicating that two operation modes can only be changed by switching the pipelines. Thus, the loop sections can be operated individually to stabilize the IS process system, and the loop operation can be transferred smoothly to the continuous operation.